VLA missiles were first introduced with the MK 46 torpedo as its payload (RUM139A). In 1996 an upgrade was implemented to allow the enhanced shallow-water capable MK 46 to be incorporated as the VLA missile payload (RUM139B). VLA missiles are delivered to the fleet as All-Up-Rounds (AURs) which consist of the VLA missile installed inside of a MK15 VLS canister. VLA missiles have two basic fleet configurations, Warshot and Exercise. VLA Warshot missiles contain a MK46 warshot torpedo. VLA Exercise missiles contain an exercise torpedo, and are used for fleet exercise firings.